Zika virus (ZIKV) is a mosquito-borne flavivirus that has emerged in the Americas with local transmission identified in 30 countries and territories as of April 2016, including Brazil. Most persons (80%) with ZIKV infection are asymptomatic and ZIKV may be sexually transmitted, placing individuals who may not have travelled at risk. Maternal-fetal transmission of ZIKV has also been documented. In April 2016, the US Centers for Disease Control and Prevention confirmed that fetal infection with ZIKV was the cause of microcephaly and other severe brain anomalies that result in permanent morbidity in surviving infants. Many questions remain regarding ZIKV infection, including the duration and potential for sexual or perinatal transmission of ZIKV from body fluids; the short and long-term reproductive outcomes of individuals infected with ZIKV; and the outcomes for infants born to men and women with either symptomatic or asymptomatic ZIKV infection. The University of Utah partnered with the United States Olympic Committee (USOC) to prepare for the 2016 Summer Olympic and Paralympic Games scheduled to occur in Brazil, the epicenter of the ZIKV outbreak in the Americas. The partnership focuses on understanding the dynamics of ZIKV infection in order to better protect the health of athletes and staff who will participate in the 2016 Games. This partnership also offers an exceptional opportunity for research that has the potential to answer many of the important research questions identified by the FOA PAR-16-106 ?Rapid Assessment of ZIKV Complications (R21).? The proposed USOC cohort is unique in that it includes men and women in their reproductive years who are interested in conceiving after the Games. Their ongoing relationship with the USOC offers an opportunity for longitudinal study that will be of enormous benefit to the Americas, including the US, and to other geographic areas facing the emergence of ZIKV. We propose the following Specific Aims: Aim 1) Determine incidence of and risk factors for ZIKV infection in a cohort of athletes coaches, staff, other personnel traveling to Brazil with the US Olympic Committee (USOC) as part of the 2016 Olympic and Paralympic games and their sexual partners through antibody testing; Aim 2a) Determine in ZIKV infected individuals, the duration of ZIKV nucleic acid detection in specific body fluids that may be associated with sexual or perinatal transmission of the virus including blood, saliva, semen, and vaginal secretions using novel PCR technology; and Aim 2b) Evaluate the reproductive outcomes of ZIKV infected individuals for one year including contraceptive use and pregnancy.